BIOREACTIVE MASS SPECTROMETER PROBES represent a true in-line consumable for Mass Spectrometry. As such they provide a vehicle with unprecedented potential to join MALDI-ToF with Biology, and set in motion an entire new direction for the pursuit of Biological, Biochemical, Analytical and Pharmacological research. By unveiling the information carried within the confines of proteins and other biologicals these research tools will advance our understanding of protein structure, protein binding and information transfer, as well as investigate pre/pro protein activation, and protein-DNA interactions. Specific aims and long-term goals of Phase I research are to secure the assay methods, derivatization chemistries and protocols, and the devices necessary to ensure the consistent production of reliable bioreactive probes for routine use in the investigation of biomolecules. PROPOSED COMMERCIAL APPLICATION The commercial potential of the bioreactive mass spectrometer probes stems from a need for routine, high-performance analytical methods in biochemical analysis. The bioreactive probes also represent one of the first truly useful consumables related to MALDI time-of-flight mass spectrometry.